How hard is the water in Brookings County, SD?
27.9 grains per gallon
A softener will pay its way here.
The median hardness measured in Brookings County, SD is 478 mg/L as calcium carbonate, which is 27.9 gpg. That is very hard on the USGS scale. It comes from 244 samples at 2 sites between 1990 and 2014, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 27.8 and 28 gpg. The whole middle of that range gives the same answer, so a test of your own tap is unlikely to change it. Confidence in the county figure: low (how it is measured).
What to do next
At 27.9 gpg a softener pays its way here. Before you buy, check the quoted unit's grain capacity against the sizing table below, and ask whether it regenerates on demand, which uses less salt than a timer. Call your utility for its own report if you are on city water.
More on sizing a softener for your household.
From 27.7 to 28.1 gpg
The softest single sample on record in Brookings County was 474.2 mg/L and the hardest 481.3 mg/L, a 1-fold gap. The top quarter of sites read above 28 gpg and the bottom quarter below 27.8 gpg.
What a softener would cost to run
For a household of 3, a 40,000-grain unit covers a week between regenerations. Expect about 610 lb of salt a year (16 bags of 40 lb, about $110), and roughly 2,346 gallons of regeneration water. Installed, most units run $1,000 to $4,500; spread over 15 years with salt, that is about $210 a year.
Sizing at 27.9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,674 | 24,000 | 204 lb |
| 2 | 3,348 | 24,000 | 407 lb |
| 4 | 6,696 | 48,000 | 815 lb |
| 6 | 10,044 | 80,000 | 1,222 lb |
Brookings County against the rest of South Dakota
Among the 55 South Dakota counties with data, Brookings County is number 21 of 55 counting from the hardest. Across the whole country it is harder than 94% of counties.
Softest in South Dakota: Dewey County at 0.5 gpg. Hardest: Hanson County at 84.7 gpg. Closest to Brookings County: Campbell County (27.8), Moody County (28), Deuel County (28.6).